The proposed study is a prospective investigation of the impact of stressful life events and social support on the health and well-being of older adults. A sample of 300 initially healthy individuals over 65 years of age will be recruited to participate in the study from Linn and Johnson counties in Iowa. These individuals will be personally interviewed every six months over a one year period, and will also complete brief mail questionnaires each month. Assessments will be taken of: (a) life stress, including both the occurence of major life events and more minor "daily hassles", (b) social support, with both quantitative and qualitative evaluations being made of thje extent to which each respondents' social relationships provide the "social provisions" identified by Robert Weiss, (c) mental health, including assessments of loneliness, life satisfaction, and depression, and (d) physical health, with self-report data being gathered on symptom status, physical functioning, global evaluations of health, and illness episodes, along with data from family members or close friends and health care providers being gathered concerning illness episodes. These data will permit an examination of a variety of theoretical issues, with advanced path analytic procedures being employed. Among the theoretical issues to be addressed are: (a) the causal impact of life stress and social support on changes in physical and mental health over time, including the issue of whether or not high levels of social support serve to "buffer" the negative effects of life stress on health and well-being; (b) the particular qualitative aspects of social support that are important in influencing the health and well-being of the elderly; (c) possible reciprocal causal effects of life stress and social support upon one another; (d) the possible causal effects of physical and mental health status upon one another, as well as upon both life stress and social support. Other minor issues to be addressed include the impact of quantitative versus qualitative measures of social support upon health and well-being and the impact of different methodologies for assessing life stress upon health and well-being. This investigation will contribute valuable knowledge to our understanding of the impact of life stress and social support upon the physical and mental health of the elderly.